This invention relates to conveying information electronically.
A computer user, for example, typically enters information into the computer via a conventional keyboard which converts finger pressure on keys to corresponding character encoded signals, or via a pointing device (a mouse, trackball, joystick, digitizing tablet, or touch screen) which converts the user's hand and finger manipulations to signals representing, for example, positions of a cursor and selections to be made.
Some devices use light, instead of moving parts, as the medium through which the user can convey the information. In some touch screens, for example, light sources lined up along the top and left edges of a computer monitor send light beams toward corresponding sensors lined up along the right and bottom edges. When the user's finger interrupts the light beams, an X,Y coordinate position is determined, U.S. Pat. No. 4,684,801.
Robots sometimes use pressure sensors to aid robotic manipulations of real objects, Pennywitt, Robot Tactile Sensing, BYTE magazine, January, 1986. One such sensor, developed by Lord Corporation, has a deformable surface overlaid on an array of pins. Each pin, when depressed, interrupts a beam passing (parallel to the deformable surface) from a photo-emitter to a photo-detector.
Two other tactile devices, described in U.S. Pat. No. 4,588,348 and U.S. Pat. No. 4,745,812, both have 4-by-4 arrays of tactile sensors arranged in rectangular grids of approximately 6-by-6 millimeters or 0.25-by-0.25 inches. They respectively use magneto-resistive elements and piezo-resistive micro-machined micro-miniature silicon devices for pressure sensing. Both patents cite robotic tactile sensing as the primary application, but mention other potential applications. The device described in the '348 patent purportedly yields data about tangential forces and torque, as well as pressure.
Devices used for generating music have included air drums having rotational acceleration sensors, a Radio Drum which uses proximity sensors and multiple finger position and pressure sensors, and a Videoharp which uses a long neon tube and DRAM sensing of the interruption of light rays from the tube to the DRAM sensor, Rubine and McAvinney, Programmable Finger-Tracking Instrument Controllers, Computer Music Journal, Volume 14, number 1, spring, 1990.
Two other music generating devices are the Bosendorfer 290 SE Recording Piano, which uses mechanical interruption of light transmitted between light-emitting diodes and phototransistors to sense the one-dimensional position and velocity of the piano keys, and the Moog Multiply-Touch-Sensitive Keyboard, which uses resistive film as a dielectric for capacitively sensing the left-and-right and forward-and-back positions of an individual keyboard key, and uses another capacitive technology to sense the up-and-down position of the key. In both the Bosendorfer and the Moog, the goal is to sense and record the performer's finger movements in sufficient detail to permit accurately reproducing the performance, Computer Music Journal, Volume 14, number 2, summer, 1990.